The Flawed Hypothesis Implication
by starfish001
Summary: Sheldon has a theory. Penny disproves it...but not before finding out something she kinda wishes she hadn't.
1. Chapter 1

A/N: I may have trampled on some canon here, but once the idea was in my head it wouldn't leave until I wrote it. I have no idea how this is going to go down with people...

* * *

It was Anything Can Happen Thursday. As usual, Howard had dragged Leonard and Raj to a bar to seek out desperate, insecure women, leaving Sheldon to opt out in favour of working on his research. Or at least, that was Sheldon's plan. The plan lasted until Penny came home from work, realised her cable had been cut off again and ensconced herself on his sofa with a bottle of wine to watch TV.

Despite his best efforts, he was unable to ignore the endless stream of character info and complex plot details she insisted on sharing with him and finally abandoned his computer to see what all the fuss was about housewives.

"Penny. I don't understand. These women appear to be financially secure, with a strong social support network. Why are they 'desperate'?"

Penny rolled her eyes as she went to pour herself another glass of wine, then frowned as the bottle emptied. She shook the few remaining drops into the still half empty glass and downed it.

"It's about _relationships_, Sheldon. You know, men and women. All the stuff that goes on between members of the opposite sex when they are actually interested in each other." She looked at him pointedly, but he remained oblivious to her gaze.

"But one of the central characters appears to be deceased. I don't understand. It just seems a very strange premise for a show." Now Sheldon was frowning.

"And I don't understand how you can happily watch people flying round in spaceships with aliens and still think Desperate Housewives is strange." She hiccupped. "Oops." She saw him open his mouth and jumped in first. "And that was not the cue for you to give me your lecture on the science of Star Trek again!" He shut his mouth and narrowed his eyes.

"Very well. But I maintain my position. I don't see the point in watching strangers engage in mating rituals. The attainment of intercourse appears to be the prime objective for most of these characters, to the detriment of all other aspects of their lives."

Penny knew she was crossing a line as soon as the words fell from her lips, but she was irritated with his dismissal of her favourite TV show and, well, the alcohol hadn't helped either.

"Well Sheldon, maybe if you had ever actually 'attained intercourse' you would understand why people spend so much time trying to do it! You have no idea what you're missing and yet you are quite happy to put down anyone who enjoys it! I mean, jeez, you're a 25 year old virgin. Don't you ever think maybe everyone else is right and that sex is actually, y'know, _fun, _and not some urge to be ignored at all cost..?"

Sheldon waited patiently for her to stop.

"Are you finished?" She nodded dumbly, a little shocked at herself. He looked like he was considering his words carefully.

"Good. Then please allow me to clarify a few things. Despite the fact that I consider the matter is really none of your concern, I do feel the need to correct you in this instance. Whilst it is true I have never had a sustained relationship with a woman, I am not, as you less than elegantly put it, a '25 year old virgin'. In fact, I am neither 25 nor a virgin. I have engaged in coitus previously and despite this I still do not feel the need to devote my life to the pursuit of it. Ergo, your entire argument is rendered unsound."

Penny was very rarely left speechless, but Sheldon's monologue had seemingly dragged all the words from her head. She was aware of a question trying to form in the void, but before it could coalesce the apartment door suddenly swung open and a drunk Leonard barrelled through it. Following closely behind him was Leslie Winkle. "Hey Sheldon, look who we bumped int…oh, erm, hi Penny…" Leonard looked from one woman to the other, struggling to focus on each.

"Hey Dr Dumbass" Leslie grinned. Sheldon's look of confusion immediately turned into a scowl, and Penny decided that this would be an excellent time to call it a night.

"Hey Leonard, Leslie…don't mind me, I was just off…." She stood.

"Oh hey, you don't have to…" Leonard trailed off as he noticed Leslie looking at him pointedly. "Ok, well I guess if you really gotta go…"

"'Night guys." She nearly ran back to her apartment.

Meanwhile, the question had formed and was now burning a hole in her brain. It was still burning when she climbed into bed.

Who the hell had Sheldon slept with?

…

Penny dreamt that night; the vivid, confused dreams only ever caused by being very, very drunk. She woke with half remembered images; of striking blue eyes impossibly close, of long fingers moving over her skin, of lips and tongues and…well, other things. She blushed and gave herself a mental shake.

Clearly Sheldon's confession had stirred something in her. He was no longer the asexual oddball she couldn't relate to; he suddenly had another dimension to him. A dimension Penny was very familiar with. It was as if two completely different worlds had just very gently collided. Of course, Sheldon himself was no different; the knowledge had changed how she was seeing him, not who he was.

She wondered why Leonard had never mentioned it when they had had those conversations about Sheldon's 'deal'. Was it really possible he didn't know? She just couldn't imagine Sheldon sharing something with her that he hadn't even talked to Leonard about. But then, maybe Leonard had never offered up a theory on his sexuality that Sheldon had felt a burning desire to disprove. She smirked a little. Sheldon couldn't bear not showing off when he had something he could prove.

She knew she should leave it alone, that questioning Sheldon further would probably be futile and would only end in one of them getting exasperated with the other. But the desire to know _who_ chewed inexplicable at the back of her mind. It wouldn't leave her alone. And there was something else.

Penny realised she felt unsettled by the knowledge. Why the fact of Sheldon's non-virginity should bug her was something she struggled with. She decided it was that so many of her assumptions about him had suddenly been undermined; she had thought she had known him and now she realised how little she _did_ know.

Unlike most guys, Sheldon had never shown any romantic interest in her: after she had seen how he tended to view the rest of the human race she had assumed he never showed interest in _any_ women. Obviously though, that wasn't true. But why should that bother her? So what if some other woman had managed to boldly go where no-one had gone before? It was irrelevant, really.

She tried to ignore the _chewing_ at the back of her mind, because she had a disturbing feeling the chewer might have vicious little green eyes, and that wasn't a thought she was prepared to entertain.

Still…Penny decided she had to know what kind of woman could seduce the beautiful mind of Sheldon Cooper.

Purely in the interests of science, of course.


	2. Chapter 2

Two weeks later, and Penny was in her element. A roomful of her friends, loud music and lots of alcohol. After her previous experience with Halloween parties she had been a bit apprehensive, but this time there were no recent exes to turn up and cause trouble…and Leonard seemed happily distracted by Leslie, dressed as they were as Robin and Wonder Woman and whispering together in the corner. A year ago she might have felt a twinge at the sight, but now she felt pleased he was moving on. Alright, Leslie was a bit, well, _odd_, but he seemed happy. She surveyed the rest of the room. Raj and Howard, dressed as some obscure comic book characters she didn't recognise, were circling the room; Raj with the aid of a few Grasshoppers and Howard assaulting her friends with his own inimitable brand of charm.

Her eyes landed on Sheldon. He was stood in the corner of the room on his own, looking uncomfortable surrounded by her friends but attempting to project an air of disinterest. He had come as Batman, and the image made her smile involuntarily. He looked kinda cute in tights. She grabbed a cup of punch and headed over to him.

"Here, I got you a drink!" She grinned at him, shouting a little over the music. "It'll help, I promise!"

He raised his eyebrows at her. "You know my feelings on alcohol, Penny."

"Yes, and I know your feelings about my friends, too! So just drink it!"

He scowled a little, looked at the crowd around him and took the drink. He took a sniff, then raised an eyebrow at her. "Vodka, rum _and_ schnapps, Penny? That doesn't strike me as being a wise combination."

"Sheldon! Drink it!" He rolled his eyes and took a wary sip. "Hmm. It is less nauseating than the sum of its ingredients would suggest. Possibly the pineapple is having some sort of mitigating influence…" She gave him a grin and left him experimenting with the drink.

An hour later and the punch was having the desired affect on the crowd. Wolowitz was whispering in the ear of one of her sluttier girlfriends, Raj had disappeared with her friend Gill with the artificial foot, and Leslie looked like she was trying to get Leonard's entire face in her mouth. Penny winced a bit and averted her eyes. She spotted Sheldon sat wonkily on the couch and felt a bit guilty for abandoning him. At some point he had taken his mask off and she could see his face was flushed. She sat down next to him and leaned over to talk into his ear.

"Are you ok?" He grinned at her. Ok, definitely drunk.

"I am having a much more agreeable time now, thank you Penny." He had turned so he was speaking into her ear and she felt his lips brush against her earlobe. The sensation reminded her of the question she needed answering.

"Sheldon, can I ask you something? It's a bit personal…" He squinted to focus on her. "Well I imagine you are capable of asking, but what I suspect you meant was _may you_ ask. And yes, you may, although I offer no guarantees that I will be prepared to answer." She sighed and bit back the urge to be sarcastic. Firstly, it would probably be lost on him, and secondly, she really wanted her answer.

"Ok. Fine. You remember the conversation we had a few weeks ago? About…erm, Desperate Housewives?" she decided on a gentle introduction.

He looked straight at her. "You mean the conversation about sex?"

She felt herself blush under his gaze. "Yeah, ok then. Sex. And you said you weren't a virgin?"

"I recall the conversation, yes." His eyes were still on hers. As usual, he clearly wasn't going to make it easy for her. So she just came out with it.

"Well, I was just wondering who it was you slept with." She tried to make it sound casual, but couldn't quite believe she was asking something so personal of him.

His eyes flickered and darkened, and he paused before answering. "That is not something I feel I should discuss with you, Penny. The nature of the experience means it is something I am endeavouring to erase from my memory. I…would prefer not to talk about it at present."

His tone remained pleasant, but Penny felt the room spin slightly. Despite his refusal to discuss it, she had got her answer.

Immediately before replying, Sheldon's eyes had glanced about the room. And for a telling fraction of a second, they had landed on Leslie Winkle.


	3. Chapter 3

Penny resumed her circulating, but her mind was spinning. Sheldon and Leslie? _Really_? Her head tried to convince her that the glance he had thrown her had been nothing, but it couldn't. She watched Sheldon as those of her friends who didn't know him tried to make small talk; how he would start waffling about string theory and they would tune out and his eyes would flit back to Leslie and Leonard. She tried to work out the look he was giving her. It certainly wasn't lust; resentment, possibly? But not of her being with Leonard, that was obvious. Was he resentful that she was still in his life? What had happened? How bad had things been between them? She thought back over all the swipes they took at each other, all the snide comments about research and theories that she now realised were clearly hiding something deeper. Something he had been trying to forget.

She figured that answered the question of why he had never told Leonard, anyway. Whether he _should_ have, however, was another matter. For a man who couldn't keep anyone else's secrets, she thought, he certainly seemed capable of keeping plenty of his own. She would definitely need to do some more digging.

…

The party eventually died out about 2am as she finally managed to wave off the guy who had been flirting with her all night. Tonight, she just hadn't been interested. Leonard had left with Leslie an hour ago, and she didn't have a clue where Howard and Raj had gone. She did, however, know exactly where Sheldon was. She surveyed the wreck of her apartment, smiling when her eyes came to rest on one of the greatest minds of the 21st century, curled up on her couch in his Batman outfit. He had his cape wrapped around him. She decided to leave him be and fell onto the bed, head spinning gently from alcohol and revelations.

She had just managed to drift off when she heard a noise from the lounge. _Crap, Sheldon must be up_. Now she'd be getting a lecture for letting him fall asleep on the couch. There was a clattering noise and she pushed open the bedroom door. The Caped Crusader was washing up.

"Sheldon, sweetie? What are you doing?"

"Oh, Penny. You're up. I'm afraid I couldn't allow you to sleep in the vicinity of this mess. You – and by association, me - are at risk from airborne mold spores."

Well he wasn't slurring his words, so the sleep had apparently had some sobering effect. Almost as soon as she thought that, a plate slipped from his grasp and shattered on the floor. She winced at the noise. Sheldon looked at the smashed plate as though it was something worthy of inspection. "Fascinating. Evidently my psychomotor skills have not completely recovered from the effects of the alcohol yet."

"Ok, Sheldon, sit down." Coffee was clearly required, since he wouldn't sleep until he'd cleaned and he couldn't clean until he was sober. He looked like he was going to protest, but then caught the look in her eye and thought better of it. He sat meekly on the sofa while she cleared up the plate fragments and brought him the drink, obediently taking a few sips.

She sat down next to him. "Ok?" Sheldon nodded. "Sooo…did you actually _enjoy_ any of tonight?" she smiled at him. He frowned as he considered the question. "I believe 'enjoyed' would be a little strong, but it was …tolerable. Certainly I am beginning to get used to the strange looks your friends always seem to give me." He looked up at her from under dark lashes.

"Aww, sweetie." She felt a twinge in her chest. "They don't mean anything by it… they just don't know you like I do." Sheldon listened, then did something she wasn't expecting; he smiled softly at her. "I appreciate your sentiment, Penny. But I believe that if I spent enough time with them that they indeed 'got to know me' then they would still not see me as you do."

She suddenly felt exposed. "How do I see you, Sheldon?"

"Well, your previous statements would indicate you at least consider me a friend. I doubt the majority of the people here tonight would be interested in maintaining a friendship with me. I appreciate it is sometimes…difficult."

Penny nearly fell of the couch. Sheldon Cooper, admitting he was…'difficult'. The coffee didn't appear to be working yet and she briefly considered taking it off him before he could sober up. She was working on an idea of how to keep him permanently half-tanked when he interrupted her thoughts.

"Penny…why were you so interested in my previous sexual encounters?" She looked up and suddenly his eyes were burning into hers. She tried to think of an answer that wouldn't make her sound, well…_jealous_. She decided to go with an edited version of the truth.

"Um. I'm not actually sure. I think it was just because it's _you_, and you don't ever seem interested in women. So it was a shock to find out that maybe you had been once…" She debated with herself, then decided to just say it. "I know it was Leslie."

She had expected him to be shocked at having been figured out, but he just accepted it with a look of resignation.

"I had wondered when you would figure it out. You did so more quickly than I anticipated; your powers of observation when it comes to social nuances are clearly highly developed."

"Sheldon…was that a compliment?"

He raised an eyebrow. "No. It was an observation."

She sighed. "So are you gonna fill me in as to how you two ended up as arch enemies? You might as well, since I know this much already." The compulsive need to know had been fighting her desire to forget all about the idea of Sheldon and another woman. As usually happened, she had decided to go with the plan that would probably involve her heart getting battered against a wall.

He pulled his cape around him tightly. "Very well. But you must agree to keep this between ourselves and also, not to laugh." He flushed slightly.

"I promise, sweetie." She couldn't promise not to get freaked out half way through and stick her fingers in her ears though, she added silently.

He looked at her dubiously, but continued.

"When I first moved to California to work at Caltech, I did not know Leonard and no one had replied to my advert for a housemate as yet. Very soon after I arrived there was a social function in which we were expected to 'shmooze' for grant money. I attempted to make my excuses but was informed that my contract could be rescinded very easily should I fail to meet the obligations placed on me by my role. So I attended. Obviously, this was an uncomfortable situation for me and I succumbed to the lure of free alcohol. At some point during the night I recall being accosted by Leslie Winkle, and we somehow ended up at my apartment. My memories of these initial interactions are very vague. Looking back on the circumstances however, I believe she was using me as some form of 'stress release'; certainly she seemed somewhat..._single-minded_ in her pursuit of coitus. In any event, the situation was not ideal. There were problems from the outset, which of course I attribute to the alcohol."

Penny had to act fast to stop the little smile that wanted to dance across her lips. Of course; with men, it was _always_ the alcohol. He continued:

"Apparently I did not perform as expected. The whole thing was over very quickly, and not in a particularly pleasurable sense. I believe she became frustrated and took it as being a personal slight, and I must admit I was not sufficiently well versed in post coital etiquette as to be able to convince her otherwise. In fact, I believe I may have made the situation worse, judging by her anger and subsequent verbal abuse."

Penny looked blank for a second as she translated the speech in her head.

"So you're saying you got really drunk, she seduced you, then you couldn't keep it up and she took the huff…? And then you opened your mouth and somehow made it worse?"

"Apparently I may have said something to insinuate that she was insufficiently attractive to overcome the problems inflicted on me by the alcohol. I don't really remember…"

"…because you were drunk, I get it. Ouch. No wonder she hates you!" Sheldon scowled at her. She ignored him. Something was bothering her about the scenario. "Sheldon, I get what you're saying, but I just can't imagine you getting drunk and hooking up with someone you hardly knew. I mean, why did you go along with it?"

He looked embarrassed. "I was at a party full of people I did not know, alone in a new city. I do not like change at the best of times, as you know, and this situation left me feeling…vulnerable. Leslie offered the potential for emotional support at the time. Or so I believed."

Penny felt a pit open in her stomach. Sheldon had felt vulnerable? That was something she couldn't imagine. At the same time as feeling sorry for him though, she couldn't deny the rush of relief that ran through her at hearing the story. She breathed out slowly. It had meant nothing to him. She didn't want to admit to herself how much that meant to _her_. She felt an overwhelming urge to giggle, but the look on Sheldon's face persuaded her that would be a very bad idea.

"Well. Thank you for telling me, Sheldon. It means a lot to me that you would trust me with something like this." Something else suddenly occurred to her.

"But…Sheldon, why did you even mention this to me in the first place? You must have known I wouldn't let it lie. Unless…." He was watching her closely as she spoke slowly, thinking aloud. "Unless you wanted me to know. But why would you do that?"

He was giving her that look again, the one that suggested he was evaluating her potential responses to what he was contemplating saying.

"I admit, I had an ulterior motive in piquing your interest thus. You said yourself, I'm not interested in women. And that's true, I'm not. But for reasons I'm not entirely sure of, I'm interested in _you_, Penny. I am conscious that people do not consider me as being part of the potential mating 'pool' as you will, but for some unfathomable reason I wanted you to be able to see me…differently." He couldn't meet her eyes. "Unfortunately, when it came to actually discussing it, it was more difficult than I anticipated."

Penny was starting to feel like the whole evening had been one long, really weird dream, and this last revelation – that Sheldon was interested in her, whatever he meant by _that_ – was doing nothing to bring her back to reality.

"Wait, you're…interested in me? Sheldon, what are you saying? Interested in the way men and women are interested in each other? Or as in the way you might be interested in a new kinda bacteria or something?"

He finally met her eyes. She thought she saw a challenge in them. "You're the expert in social behaviour here, Penny. What do you think?"

She thought lots of things. She thought of how they were complete polar opposites, how they fought like cat and dog, how utterly _infuriating_ he could be. She thought of how he tested her, challenged her more than anyone else she had ever met, how she had learnt so much from him. She thought of how sweet he could be, how his casual comments about her attractiveness meant so much because he had no hidden agenda. She thought of how cute he looked in the cape and wondered when his knee had started pressing against hers. She thought of how amazing it felt when he smiled at her.

She thought of how she had felt over the last two weeks, imagining him with another woman.

She thought of how she felt _now, _his eyes boring into her.

She dredged a phrase from her memory.

"I think…I think your methodology was flawed, Sheldon. You can't judge something as complex as sex on one bad experience." He raised a single enquiring eyebrow, and she met his eyes with her own challenge. "I think you need to repeat your experiment."

He swallowed hard before he replied, and she was briefly transfixed by that bobbing adams apple. She fought the urge to kiss it. His voice was hoarse.

"You present a fascinating supposition. Would you perhaps be interested in assisting me in the experiment?"

Almost before he had finished she was on top of him, cupping his face and pressing her mouth against his. She was pretty sure the alcohol was responsible for the fact that he kissed her back without first insisting she rinse with an antibacterial mouthwash. She was also praying the alcohol wouldn't be affecting any areas other than his brain, but from what she was feeling as she ground against him that didn't seem like it was going to be an issue. Although…

"Sheldon?"

He looked at her enquiringly.

"I have to ask…is that a batgrenade on your utility belt or are you just pleased to see me?" she deadpanned. He frowned, and she giggled, euphoric with the strangeness of the situation.

"I do not understand the question…" She silenced him with another kiss, slipping her tongue into his mouth as he made a surprised little noise.

His hands started on her hips before wandering down to her thighs in search of flesh, denied as they had been by the fabric of her dress. She had come dressed as Alice, and as she snuck a glance at the man beneath her the thought occurred that she was well and truly through the looking-glass tonight. Then Sheldon's hands were sliding under her skirt and she stopped thinking _anything_ for a while.

Afterwards they lay together on the bed, Penny dozing whilst Sheldon analysed. After the experiment on the couch had proven successful, he had proposed altering the location variable to thoroughly test the reliability of their findings. It would appear that having successful coitus did actually increase the desire to achieve it more regularly. Hm. He wondered if there was a research paper in there somewhere. He briefly debated informing Leslie of his findings, then rejected the idea as some ancient instinct for self-preservation kicked in. He had a brief moment of self-doubt as he considered whether any of his other theories were untenable, but promptly rejected the notion. This was clearly an unfortunate aberration.

Although, he had to admit as he watched Penny sleep, he was quite happy to have his initial hypothesis disproved…just this once.

…

Penny heard Sheldon shuffle next to her, and then smiled to herself as his hand hovered uncertainly above her before gently coming to rest on her hip. Images of the last few hours floated through her head, and her final hazy thought before drifting into a contented sleep was just how _fun_ science could be, when you had someone to experiment with...


End file.
